The Role of Type VI Secretion System Effectors in Target Cell Lysis and Subsequent Horizontal Gene Transfer

• Published in: Cell reports (Cambridge) Vol. 21; no. 13; pp. 3927 - 3940
• Main Authors: Ringel, Peter David, Hu, Di, Basler, Marek
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 26.12.2017; Elsevier
• Subjects: bacterial competition; cell lysis; effectors; horizontal gene transfer; type VI secretion system; effectors; type VI secretion system; horizontal gene transfer; bacterial competition; cell lysis
• ISSN: 2211-1247; 2211-1247
• DOI: 10.1016/j.celrep.2017.12.020

Bacteria use type VI secretion systems (T6SSs) to manipulate host cells during pathogenesis or to kill competing bacteria, which, in some cases, increases horizontal gene transfer. These functions largely depend on T6SS regulation, dynamics, and the set of effectors that the system delivers into the target cells. Here, we show that Acinetobacter baylyi ADP1 assembles a highly dynamic T6SS capable of killing and lysing bacterial cells. T6SS function depends on conserved T6SS components as well as Acinetobacter-specific genes of unknown function. Five different effectors, encoded next to VgrG or PAAR proteins and their cognate immunity proteins, cause distinct changes in the prey cells, resulting in various degrees of their lysis. Prey lysis correlates with the rate of DNA transfer from prey to predator, suggesting that lytic effectors are required for efficient T6SS-dependent horizontal gene transfer in naturally competent bacteria. [Display omitted] •Acinetobacter baylyi assembles a dynamic antibacterial type VI secretion system•Killing and lysis of prey bacteria differs for each of the five effectors•Gene transfer from prey to predator depends on delivery of lytic effectors Ringel et al. show that naturally competent Acinetobacter baylyi ADP1 uses its type VI secretion system to kill bacterial competition by delivery of five different effectors. Lysis of prey cells induced by delivery of lytic effectors is required for efficient transfer of DNA from prey to predator.